Seat cushion side

Switch the ignition to off.
Disconnect the negative battery terminal and wait for 1 min or more. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .)
Remove the rear seat. (See REAR SEAT BACK REMOVAL/INSTALLATION .)
Inspect for continuity between the seat warmer unit connector terminal A and B.

Fig 1: Checking Continuity Between Seat Warmer Unit Connector Terminal A And B
Courtesy of MAZDA MOTORS CORP.

Fig 2: Seat Warmer Unit Connector Terminal A And B Continuity Chart
Courtesy of MAZDA MOTORS CORP.
- If not as specified, replace the rear seat cushion pad. (See REAR SEAT CUSHION TRIM REMOVAL/INSTALLATION .)
Measure the temperature around the thermostat.

Fig 3: Measuring Temperature Around Thermostat
Courtesy of MAZDA MOTORS CORP.
NOTE:
- To make the temperature around the thermostat at the normal temperature, the seat warmer is left for 30 minutes or more while turned off.
Measure the resistance between the seat warmer unit connector terminal C and D, records with the surrounding temperature of the thermostat measured beforehand.
Connect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .)
Connect the seat warmer unit connector.
Switch the seat warmer switch to Lo position, and warm the seat warmer.
Measure the resistance between the seat warmer unit connector terminal C and D, and record it.
Switch the seat warmer switch to High position, and warm the seat warmer.
Measure the resistance between the seat warmer unit connector terminal C and D, it is confirmed that there is a change from the resistance recorded beforehand.
- If the change in resistance cannot be confirmed, replace the rear seat cushion pad. (See REAR SEAT CUSHION TRIM REMOVAL/INSTALLATION .)